A study of periselectivity in the thermal cyclisation reactions of diene-conjugated diazo compounds: 1,7-cyclisation as a route to 3H-1,2-diazepines and 1,5-cyclisation leading to new rearrangement reactions of 3H-pyrazoles
作者:Ian R. Robertson、John T. Sharp
DOI:10.1016/s0040-4020(01)82434-0
日期:1984.1
A range of diene-conjugated diazo compounds has been generated by the thermal decomposition of the sodium salts of the tosylhydrazones of 1-acyl-1, 3-dienes. Those of type (21) with a relationship of the diazo group and the γ, δ-double bond having a hydrogen atom at the diene terminus cyclised only by 1,7 ring closure to give 3-1,2-diazepines (23). This mode of cyclisation was inhibited by the presence
Palladium-Catalyzed Carbonylative Cyclization of Unsaturated Aryl Iodides and Dienyl Triflates, Iodides, and Bromides to Indanones and 2-Cyclopentenones
作者:Steve V. Gagnier、Richard C. Larock
DOI:10.1021/ja0212009
日期:2003.4.1
carbonylative cyclization is particularly effective on substrates that contain a terminal olefin. The proposed mechanism for this annulation includes (1) Pd(OAc)(2) reduction to the active palladium(0) catalyst, (2) oxidative addition of the organichalide or triflate to Pd(0), (3) coordination and insertion of carbon monoxide to produce an acylpalladium intermediate, (4) acylpalladation of the neighboring
Regioselective Simmons–Smith-type cyclopropanations of polyalkenes enabled by transition metal catalysis
作者:Jacob Werth、Christopher Uyeda
DOI:10.1039/c7sc04861k
日期:——
A cobalt catalyst imparts a high degree of regioselectivity in the reductive cyclopropanation of polyalkenes.
一种钴催化剂在多烯的还原环丙烷化反应中赋予高度的位置选择性。
Modular Construction of Fluoroarenes from a New Difluorinated Building Block by Cross-Coupling/Electrocyclisation/Dehydrofluorination Reactions
作者:Jonathan M. Percy、Helena Emerson、James W. B. Fyfe、Alan R. Kennedy、Sergej Maciuk、David Orr、Lucie Rathouská、Joanna M. Redmond、Peter G. Wilson
DOI:10.1002/chem.201601584
日期:2016.8.16
were used to assemble precursors to 6π‐electrocyclisations of three different types. Electrocyclisations took place at temperatures between 90 and 240 °C, depending on the central component of the π‐system; nonaromatic trienes were most reactive, but even systems that required the temporary dearomatisation of two arenyl subunits underwent electrocyclisation, albeit at elevated temperatures. Photochemical
Cationic gold(I) complexes with hollow‐shaped triethynylphosphine ligands efficiently catalyzed intramolecular [2+2] cycloaddition of 1,9‐enynes to afford cyclobutene‐fused eight‐membered carbocycles that were difficult to synthesize by other catalytic systems. Various 1,9‐enynes with carbon linkers with or without a fused ring underwent efficient [2+2] cycloaddition with 5 mol% of the Au catalyst